This invention relates to a needle for the spray injection into meat pieces of brine obtained from a series of additives and/or ingredients which are indispensable for the process of curing the meat pieces, generally baked ham or shoulder meat, in order to assure the colouring and the flavour, of the type comprising a tubular body provided with an axial duct with radial holes having a diameter which is apt to assure the spraying under pressure, said holes being distributed along the tubular body of the needle and piercing its wall right through, a holding end portion connected to an end of said tubular body and provided with a fastening/gripping zone, and a pointed tip connected to the other end of said tubular body.
As publications of prior art can be cited patents SU-A-1 629 017, FR 2 470 545, CH-A-541 930, AU-D894 772, FR-A-2 366 797, DE-A-19 13 072 and U.S. Pat. No. 4,690,046.
The known needles of this kind are of two types depending on the existing operating procedures (mode of injecting the brine into the meat):
a) the low-pressure process (with pressures of the order of 4 kg/cm2) which uses needles having in general 2 or 4 orthogonal radial holes with a diameter of the order of more than one millimetre, said needles depositing the brine during the passage of the needle through the meat, thereby forming brine deposits which must be thereafter spread by mechanical action. With this process the use of higher pressures would damage the structure of the meat, since the jet would cause the separation and even the rupturing of the meat fibres; PA1 b) the high-pressure process (with pressures of the order of 8 to 12 kg/cm2), more effective, which uses needles with a bigger number of radial holes, in general from 11 to 14, distributed at different heights along the needle body, said holes having a smaller diameter, generally of the order of some 0.6 mm, the brine being spray injected under pressure once the needles have been arrested in position once having been driven into the meat piece. Thus once the needles have been driven into the meat piece and have been arrested at the end of their travel the brine is then injected into the meat with a "spray" or "nebulizator" effect, thereby introducing into the mass of meat a volumetrically dosed quantity of brine which is distributed in a very homogeneous way throughout the whole meat piece. PA1 a more homogeneous distribution of the brine, thus allowing the latter to penetrate the muscle fibres in form of microdrops without damaging them, avoiding the brine deposits between fibres; PA1 a higher accuracy of the injected brine percentage; PA1 a better cleaning of the needles (with the new needles). PA1 the bottom of the axial duct, which is constituted by the upper wall of the pointed tip connected to the lower end of said cavity, comprises a plane in the shape of an inclined trough whose profile shows a width which decreases from top to bottom, in such a way that its bottom ends in a flushing connection with the lowest part of the inner wall of the radial hole which is closest to the needle tip; PA1 each cylindrically shaped radial hole comprises a bellmouthed section its mouth leading to the outside of the cylindrical body, said section being of a shorter length with respect to that of the corresponding cylindrical part.
In both solutions the brine excess is recycled thus causing, because of the meat microfibres it contains, the clogging of the holes, and mainly of the last one at the lowest part in the vicinity of the needle tip (an important part of the meat piece hence not receiving any sprayed brine), this complicating the regular needle cleaning tasks which are mandatory. This phenomenon is all the more important (difficulty of the cleaning and clogging frequency) the smaller the needle holes are.
The clogging of the hole which is closest to the needle tip determines an accumulation of residual matter on it which is hardly eliminable when cleaning the needle, and this can cause on the long term the clogging of the other holes and determines besides a pressure increase at the remaining open holes of the needle, with the consequent irregularities in the brine distribution.